#include <stdio.h>

void swap(int *p, int *q);

int main(void)
{
    int j = 7, k = 8;
    printf(" %d", j);
    printf(" %d\n", k);

    swap(&j, &k);

    printf(" %d", j);
    printf(" %d\n", k);
}

void swap(int *p, int *q)
{
    int by;

    by = *p;
    *p = *q;
    *q = by;
}

